The reason I think we need new furs and antlers for the great one red deer is that there is only one fur variation which is the lowest amount of fur variations of any great one. Also all the antlers for them look very similar to the point that the majority of people that have a great one red deer do not know what exact antler variation they have.
Another reason we need new furs and antlers for the great one red deer is because there is so much potential for good fur and antler variation for red deer.
Also the great one red deer looks so similar to one another if you have two great one red deer you can barely tell the differences between them